Arterial sets for hemodialysis are known to conventionally carry a blood flow tubing between a connector for the arterial fistula of the patient at one end of the set and a connector to the dialyzer at the other end of the set. Between the set ends, an enlarged-diameter pump tube segment is provided, being tubing which fits into the track of a roller pump for rolling compression by the rollers of the pump. This provides the necessary pressure to circulate the blood at a desired flow rate through the entire system from the patient, through the dialyzer, and back to the patient.
Additionally, both arterial and venous dialysis sets typically carry a so-called xe2x80x9cdrip chamberxe2x80x9d, although at current blood flows through dialyzers, the volume of blood passing through the set is much greater than that represented by a xe2x80x9cdripxe2x80x9d.
Hemodialysis is a relatively expensive medical procedure, since it is typically performed about three times a week on a continuing basis through the remaining life of the patient, or at least until a kidney transplant is obtained. Thus, there is significant need to reduce the cost of dialysis, which of course includes the cost of the blood sets used, and are typically disposed of after one use. Even a relatively small cost reduction in the manufacture of blood sets for dialysis can result in significant cost savings, because of the large numbers of such blood sets that are used.
At the present time, blood sets for dialysis which carry a pump segment substantially all have such pump segments that terminate in branching connectors. The branching connectors also receive the ends of the other portions of the blood flow conduit of the set, with such flow conduit portions being generally of less outer diameter than the pump segment. Also, each of the connectors at opposite ends of the pump segment typically carry a branch line which connects with the pump segment at a 90xc2x0 angle. One of these branch lines is for connection to a set for saline solution supply, while the other of the branch lines typically connects to a source of heparin.
Pump sets are typically packaged in a rolled-up manner of substantially circular appearance, so that the package may be compact and neat. However, because of the presence of the perpendicular branch lines, the rolling of the set into a circular array for packaging is not easily done in an automated manner, but rather must be accomplished substantially by hand. This of course adds to the cost of packaging of the set, which adds to the overall set cost.
In addition, this 90 degree branch attachment results in complicated set-up, twisted lines, and the like by the following action: The orientation of the inlet 90 degree branch can by manipulated by the healthcare worker when the pump segment connector is attached to the first end of the U-shaped pump housing. For example, the inlet end pump segment connector can be oriented so the 90 degree branch can be pointed outwardly, parallel to the face plate of the machine. This facilitates easy attachment of the branch (IV) line to the typical line that connects at the inlet end of the pump tubing saline source.
However, the outlet 90 degree branch attachment cannot be so easily manipulated because its orientation is determined by the pronation (twisting) of the pump segment, being rotated in its U-shape by the pump rollers. Thus, while it is desirable for the outlet 90 degree branch attachment to be pointed outwardly, parallel to the face of the machine (for attachment to the heparin syringe pump), it ends up in a random location, pointing to the right, left, forward or back towards the face plate.
This leads to difficult set-up and even kinks in this attachment line as it must be redirected. Finally, the pump segment tends to continue to pronate during the procedure through the continued rotation of the pump rollers. The 90 degree attachment and connected line thus gets further twisted.
By this invention, a set for conveying blood between a patient and a hemodialyzer (or another blood treatment apparatus) is provided, in which the set is significantly more capable of automated rolling into a circular array, so that the sets may be packaged in a more automated packaging process than the sets of the prior art. The set of this invention may be automatically rolled, installed in a package, and sealed therein without being touched by human hands. Thus, the set of this invention may exhibit a reduced overall cost, when compared with prior art sets which are otherwise comparable. Also, by this invention a set is provided in which the set up of the pump segment attachment lines is more convenient and less likely to kink.
In accordance with this invention, a set for conveying blood between a patient and blood treatment apparatus is provided which comprises a blood flow conduit means for connecting the conduit with a patient""s vascular system and means for connecting the conduit with the blood treatment apparatus. A portion of the conduit of the set comprises a tubular pump segment which is connected at least at one pump segment end with a connector. The above connector or connectors also each connect in substantially straight-line relation to other portions of the blood flow conduit.
At least one of the connectors also connects to a branch line in a relation which is substantially parallel to the connection of the connected other portion of the blood flow conduit (and may also be generally parallel to the connection of the pump segment). Typically, both of the connectors at opposed ends of the pump segment each carry the substantially parallel branch line connection with a branch conduit.
By this means, the set of this invention is more capable of being rolled up and packaged in an automated manner than corresponding prior art sets. Specifically, the rolled-up set will be free of tubular members which project inwardly from the circular set in generally radial manner, so that the space within the rolled-up set is essentially free of set components.
Also, by this means the branch conduits may be shorter. Because pronation of the pump segment connector does not orient the conduit in the wrong direction, the branch conduits can be shorter, while still being capable to mate distally with a machine mounted connector, for example a heparin line conduit connecting to a syringe may mate with the connector of this invention. Also, set up is easier, and kinks are less likely.
The tubular pump segment is typically of greater diameter than the other portions of the blood flow conduit adjacent the connectors, with the exception of course of a drip chamber and the like, which is typically present. Also, the branch line or lines present which connect with the connectors at the ends of the pump segment are typically of less diameter than the other portions of the blood flow conduit adjacent the connectors. Specifically, it is preferred for the set of this invention to have a pump segment of an outer diameter of 8.5 to 12.5 millimeters; a blood flow conduit adjacent the connectors having an outer diameter of about 4.5 to 7.5 millimeters; and the branch line or branch lines having an outer diameter of about 1.6 to 4.0 millimeters. Some sets of the prior art have tubing diameters similar to the above.
Thus, a set for hemodialysis or the like is provided in which the functioning is equivalent to or better than that of prior art sets, but the set may be rolled by automated means into a circular array without inconvenient, inwardly extending branching sets from the circular array toward the origin of the circle, which facilitates automated packaging of the set of this invention and eliminates branch conduit kinking and permits a reduction in the length of branch lines.